import 'class.dart';

class Student extends Person{
  void study(){
    print('Learning...');
  }
  @override
  void work(){
    print('Working? Impossible!');
  }
}

void main(){
  var student = new Student();
  student.study();
  student.name='Tom';
  student.age=15;
  student.work();
  Person person = new Student();
  if(person is Student){
    person.study();
  }
  person as Student;
  person.study();
}
